#![allow(dead_code, unused_imports, unused_macros, non_snake_case)]
use proconio::{
    input,
    marker::{Bytes, Chars, Usize1},
};

fn main() {
    input! {
        n: usize,
        h: usize,
        l: [(usize, usize); n],
    }

    let mut sum = vec![0; h + 1];
    for (a, b) in l {
        sum[a] += 1;
        sum[b + 1] -= 1;
    }

    for i in 1..=h {
        sum[i] += sum[i - 1];
    }
    println!("{}", sum.iter().max().unwrap());
}